Agreed. If she already has a selection of EF lenses (not EFS), stick with Canon. Go for a recently made body and avoid the older 600 models - Quite a few of the older bodies are suffering from a Canon Wheeze. This is due to the light seals breaking down and gumming up the shutter blinds.
Rather than picking a random body from ebay, I'd recommend being able to give it a close look and exercise the shutter a few times before purchasing. Look for oily smears on the shutter blinds and reject anything that is even slightly suspect.